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Journal of Materials Science & Technology 2024年第1期168卷 124-130页

作者： Yiqing Wei Jiaqi Liu Zien Cheng Pengfei Jiang zizhen zhou Bin Zhang Guoyu Wang Guang Han Xu Lu Xiaoyuan zhou Center of Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China College of Chemistry and Chemical Engineering Chongqing UniversityChongqing 401331China Analytical and Testing Center Chongqing UniversityChongqing 401331China

Tetrahedrite,an Earth-abundant natural mineral,has attracted extensive research interest because of its excellent thermoelectric performance.Herein,tetrahedrite samples comprising Cu-poor Cu_(12)Sb_(4)S_(13)and Cu-rich Cu_(14)Sb_(4)S_(13)phases have been synthesized using a colloidal method,in which the ratio of two phases is manipulated by controlling the synthesis temperature to improve the thermoelectric perfor-mance.It is found that an ultralow total thermal conductivity of∼0.3 W m^(−1)K^(−1)at 723 K is realized in the sample with a Cu-rich phase fraction of∼50%,which can be attributed to maximized phonon scattering by phase boundaries.As a result,combined with a decent power factor,this sample obtains an optimal zT of 1.15,which is about 85%higher than that of the sample with a Cu-rich phase fraction of∼64%and comparable to zT values of other eco-friendly,abundant Cu-based thermoelectric materials.This work demonstrates an effective synthesis-temperature-dependent phase composition manipulation strategy toward enhanced thermoelectric performance in tetrahedrites.

关键词： Tetrahedrite Thermoelectric Colloidal method Phase manipulation Thermal conductivity

Realizing ultrahigh average figure of merit through manipulating layered phonon-electron decoupling

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Science China Materials 2022年第7期65卷 1987-1988页

作者： zizhen zhou Xiaoyuan zhou Center of Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331China

Developing advanced thermoelectric materials for waste heat recovery is a promising strategy to meet the growing energy demand and low-carbon economy [1].The thermoelectric performance is evaluated by the dimensionles... 详细信息

关键词： ultrahigh Seebeck phonon

High-performance magnesium-based thermoelectric materials:Progress and challenges

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Journal of Magnesium and Alloys 2022年第7期10卷 1719-1736页

作者： zizhen zhou Guang Han Xu Lu Guoyu Wang Xiaoyuan zhou Center of Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331PR China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044PR China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714PR China Analytical and Testing Center Chongqing UniversityChongqing 401331PR China

Magnesium-based materials have been regarded as promising candidates for large-scale,high-efficiency thermoelectric applications,owing to their excellent dimensionless figure of merit,high abundance,and low cost.In this review,we comprehensively summarize the recent advances of Mg-based thermoelectrics,including Mg_(2)X(X=Si,Ge,Sn),Mg3(Sb,Bi)_(2),andα-MgAgSb,from both material and device level.Their electrical and thermal transport properties are first elucidated based on the crystallographic characteristics,band structures,and phonon dispersions.We then review the optimization strategies towards higher thermoelectric performance,as well as the device applications of Mg-based thermoelectric materials and the related engineering issues.By highlighting the challenges and possible solutions in the end,this review intends to offer perspectives on the future research work to further enhance the performance of Mg-based materials for practical applications.

关键词： Thermoelectric Mg-based materials Mg_(2)(Si,Ge,Sn) Mg_(3)Sb_(2) MgAgSb Thermoelectric device

Planar Zintl-phase high-temperature thermoelectric materials XCuSb(X=Ca,Sr,Ba)with low lattice thermal conductivity

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Journal of Advanced Ceramics 2022年第10期11卷 1604-1612页

作者： Sikang ZHENG Kunling PENG Shijuan XIAO zizhen zhou Xu LU Guang HAN Bin ZHANG Guoyu WANG Xiaoyuan zhou College of Physics and Center of Quantum Materials&Devices Chongqing UniversityChongqing 401331China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China Analytical and Testing Center Chongqing UniversityChongqing 401331China Interdisciplinary Center for Fundamental and Frontier Sciences Nanjing University of Science and TechnologyJiangyin 214443China

A recent discovery of high-performance Mg_(3)Sb_(2) has ignited tremendous research activities in searching for novel Zintl-phase compounds as promising thermoelectric materials.Herein,a series of planar Zintl-phase XCuSb(X=Ca,Sr,Ba)thermoelectric materials are developed by vacuum induction melting.All these compounds exhibit high carrier mobilities and intrinsic low lattice thermal conductivities(below 1 W·m^(−1)·K^(−1) at 1010 K),resulting in peak p-type zT values of 0.14,0.30,and 0.48 for CaCuSb,SrCuSb,and BaCuSb,respectively.By using BaCuSb as a prototypical example,the origins of low lattice thermal conductivity are attributed to the strong interlayer vibrational anharmonicity of Cu–Sb honeycomb sublattice.Moreover,the first-principles calculations reveal that n-type BaCuSb can achieve superior thermoelectric performance with the peak zT beyond 1.1 because of larger conducting band degeneracy.This work sheds light on the high-temperature thermoelectric potential of planar Zintl compounds,thereby stimulating intense interest in the investigation of this unexplored material family for higher zT values.

关键词： Zintl-phase thermoelectric materials honeycomb lattice intrinsic lowκ_(L)

Realizing Cd and Ag codoping in p-type Mg_(3)Sb_(2)toward high thermoelectric performance

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镁合金学报(英文) 2023年第7期11卷 2486-2494页

作者： Shijuan Xiao Kunling Peng zizhen zhou Huan Wang Sikang Zheng Xu Lu Guang Han Guoyu Wang Xiaoyuan zhou College of Physics Chongqing UniversityChongqing 401331China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China Analytical and Testing Center Chongqing UniversityChongqing 401331China

Mg_(3)Sb_(2)has attracted intensive attention as a typical Zintl-type thermoelectric material.Despite the exceptional thermoelectric performance in n-type Mg_(3)Sb_(2),the dimensionless figure of merit(zT)of p-type Mg_(3)Sb_(2)remains lower than 1,which is mainly attributed to its inferior electrical properties.Herein,we synergistically optimize the thermoelectric properties of p-type Mg_(3)Sb_(2)materials via codoping of Cd and Ag,which were synthesized by high-energy ball milling combined with hot pressing.It is found that Cd doping not only increases the carrier mobility of p-type Mg_(3)Sb_(2),but also diminishes its thermal conductivity(κ_(tot)),with Mg_(2.85)Cd_(0.5)Sb_(2)achieving a lowκtot value of∼0.67 W m^(−1)K^(−1)at room temperature.Further Ag doping elevates the carrier concentration,so that the power factor is optimized over the entire temperature range.Eventually,a peak zT of∼0.75 at 773 K and an excellent average zT of∼0.41 over 300−773 K are obtained in Mg_(2.82)Ag_(0.03)Cd_(0.5)Sb_(2),which are∼240%and∼490%higher than those of pristine Mg_(3.4)Sb_(2),respectively.This study provides an effective pathway to synergistically improve the thermoelectric performance of p-type Mg_(3)Sb_(2)by codoping Cd and Ag,which is beneficial to the future applications of Mg_(3)Sb_(2)-based thermoelectric materials.

关键词： Thermoelectric p-type Mg_(3)Sb_(2) Cd and Ag codoping Lattice thermal conductivity Carrier concentration

Band modification towards high thermoelectric performance of SnSb_(2)Te_(4) with strong anharmonicity driven by cation disorder

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Journal of Materials Science & Technology 2023年第23期154卷 140-148页

作者： Hong Wu Peng Chen zizhen zhou De Zhang Xiangnan Gong Bin Zhang Yang zhou Kunling Peng Yanci Yan Guiwen Wang Jun Liu Dengfeng Li Guang Han Guoyu Wang Xu Lu Xiaoyuan zhou School of Science Chongqing University of Posts and Telecommunications Chongqing 400065 China College of Physics and Center for Quantum Materials & Devices Chongqing University Chongqing 401331 China College of Materials Science and Engineering Chongqing University Chongqing 400044 China Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing 400714 China Analytical and Testing Center of Chongqing University Chongqing 401331 China Interdisciplinary Center for Fundamental and Frontier Sciences Nanjing University of Science and Technology Jiangyin 214443 China

As a typical (IV–VI)_(x)(V_(2)VI_(3))_(y) compound, the tetradymite-like layered SnSb_(2)Te_(4) -based compounds have attracted increasing attention in the thermoelectric community owing to the intrinsically low lattice thermal conductivity. Nevertheless, the effect of cations disorder on the inherent physical characteristics remains puzzling, and its inferior Seebeck coefficient is the bottleneck to achieving high thermoelectric performance. In this work, the thermoelectric properties of polycrystalline In_(x)Sn_(1−x)Sb_(2)(Te_(1−y)Se_(y))_(4) (0≤x≤0.1,0≤y≤0.15) samples are comprehensively investigated. In conjunction with the calculated band structure and experimental results, the Seebeck coefficient and power factor are markedly improved after the introduction of indium and selenium, which originates from the combined effects of the emergent resonant states and converged valence bands along with optimal carrier concentration. Additionally, compared with the ordered lattice structure, the disordered cations occupancy in SnSb_(2)Te_(4) further strengthens lattice anharmonicity and reduces phonon group velocity verified by first-principles calculations, securing intrinsically low lattice thermal conductivity. Finally, a record zT value of ∼0.6 at 670 K and an average zT of ∼0.4 between 320 and 720 K are obtained in the In0.1 Sn0.9 Sb2 Te3.4 Se0.6 sample, being one of the highest zT values among SnSb2 Te4 -based materials. This work not only demonstrates that SnSb2 Te4 -based compounds are promising thermoelectric candidates, but also provides guidance for the promotion of thermoelectric performance in a broad temperature range.

关键词： Thermoelectric SnSb_(2)Te_(4) Lattice anharmonicity Resonant level Band Convergence

Sediment pollution characteristics and in situ control in a deep drinking water reservoir

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Journal of Environmental Sciences 2017年第2期29卷 223-231页

作者： zizhen zhou Tinglin Huang Yang Li Weixing Ma Shilei zhou Shenghai Long Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi'an University of Architecture and TechnologyXi'an 710055China Shaanxi Key Laboratory of Environmental Engineering Xi'an University of Architecture and TechnologyXi'an 710055China

Sediment pollution characteristics, in situ sediment release potential, and in situ inhibition of sediment release were investigated in a drinking water reservoir. Results showed that organic carbon（OC）, total nitrogen（TN）, and total phosphorus（TP） in sediments increased from the reservoir mouth to the main reservoir. Fraction analysis indicated that nitrogen in ion exchangeable form and Na OH-extractable P（Fe/Al-P） accounted for 43% and 26% of TN and TP in sediments of the main reservoir. The Risk Assessment Code for metal elements showed that Fe and Mn posed high to very high risk. The results of the in situ reactor experiment in the main reservoir showed the same trends as those observed in the natural state of the reservoir in 2011 and 2012; the maximum concentrations of total OC, TN, TP, Fe,and Mn reached 4.42 mg/L, 3.33 mg/L, 0.22 mg/L, 2.56 mg/L, and 0.61 mg/L, respectively. An in situ sediment release inhibition technology, the water-lifting aerator, was utilized in the reservoir. The results of operating the water-lifting aerator indicated that sediment release was successfully inhibited and that OC, TN, TP, Fe, and Mn in surface sediment could be reduced by 13.25%, 15.23%, 14.10%, 5.32%, and 3.94%, respectively.

关键词： Sediment pollution In situ reactor Water-lifting aerator Sediment release inhibition

Destratification and oxygenation efficiency of a water-lifting aerator system in a deep reservoir:Implications for optimal operation

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Journal of Environmental Sciences 2018年第11期30卷 9-19页

作者： Yang Li Tinglin Huang Xinlin Tan zizhen zhou Weixing Ma Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi'an University of Architecture and Technology Shaanxi Key Laboratory of Environmental Engineering Xi'an University of Architecture and Technology

Thermal stratification is a common phenomenon in lakes and reservoirs and has a significant influence on water quality dynamics. Heihe Reservoir is a canyon-shaped reservoir in Shaanxi Province with strong thermal stratification. Therefore, eight water-lifting aerators （WLAs） were installed in this reservoir, which could overcome thermal stratification and increase oxygenation with gas flows between 20 and 50 m3/hr, and oxygenate the hypolimnion with gas flows less than 20 m3/hr. To examine the destratification efficiency of the WLA system, we used a three- dimensional hydrodynamic module based on MIKE 3 to simulate the thermal structure of Heihe Reservoir and compared the simulations with measured data. Results showed that operation of the WLA system promoted water mixing and effectively oxygenated the hypolimnion. Through the established energy utilization assessment method, the energy utilization efficiency of the WLA system was between 5.36% and 7.30%, indicating the capability of the technique for destratification in such a large reservoir. When the surface water temperature dropped to the theoretical mixed water temperature calculated by the energy utilization assessment method, reducing gas flow could save energy. This would prevent anaerobic conditions from occurring in the bottom water and maintain good water quality in Heihe Reservoir.

关键词： Reservoir Thermal stratification Numerical simulation Water-lifting aerator Mixing Oxygenation

基于改进YOLO v7轻量化模型的自然果园环境下苹果识别方法

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农业机械学报 2024年第3期55卷 231-242,262页

作者：张震周俊江自真韩宏琪南京农业大学工学院南京210031

针对自然果园环境下苹果果实识别中,传统的目标检测算法往往很难在检测模型的检测精度、速度和轻量化方面实现平衡,提出了一种基于改进YOLO v7的轻量化苹果检测模型。首先,引入部分卷积(Partial convolution, PConv)替换多分支堆叠模块... 详细信息

针对自然果园环境下苹果果实识别中,传统的目标检测算法往往很难在检测模型的检测精度、速度和轻量化方面实现平衡,提出了一种基于改进YOLO v7的轻量化苹果检测模型。首先,引入部分卷积(Partial convolution, PConv)替换多分支堆叠模块中的部分常规卷积进行轻量化改进,以降低模型的参数量和计算量;其次,添加轻量化的高效通道注意力(Efficient channel attention, ECA)模块以提高网络的特征提取能力,改善复杂环境下遮挡目标的错检漏检问题;在模型训练过程中采用基于麻雀搜索算法(Sparrow search algorithm, SSA)的学习率优化策略来进一步提高模型的检测精度。试验结果显示:相比于YOLO v7原始模型,改进后模型的精确率、召回率和平均精度分别提高4.15、0.38、1.39个百分点,其参数量和计算量分别降低22.93%和27.41%,在GPU和CPU上检测单幅图像的平均用时分别减少0.003 s和0.014 s。结果表明,改进后的模型可以实时准确地识别复杂果园环境中的苹果,模型参数量和计算量较小,适合部署于苹果采摘机器人的嵌入式设备上,为实现苹果的无人化智能采摘奠定了基础。

关键词：苹果识别自然果园环境 YOLO v7 PConv 高效通道注意力机制麻雀搜索算法

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High-throughput prediction of the carrier relaxation time via data-driven descriptor

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npj Computational Materials 2020年第1期6卷 435-440页

作者： zizhen zhou Guohua Cao Jianghui Liu Huijun Liu Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education and School of Physics and Technology Wuhan UniversityWuhan 430072China Center for Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331China International Center for Quantum Design of Functional Materials(ICQD) Hefei National Laboratory for Physical Sciences at the Microscaleand Synergetic Innovation Center of Quantum Information and Quantum PhysicsUniversity of Science and Technology of ChinaHefeiAnhui 230026China

It has been demonstrated that many promising thermoelectric materials,such as tetradymite compounds are also threedimensional topological insulators.In both cases,a fundamental question is the evaluation of carrier relaxation time,which is usually a rough task due to the complicated scattering mechanisms.Previous works using the simple deformation potential theory or considering complete electron-phonon coupling are,however,restricted to small systems.By adopting a data-driven method named SISSO(Sure Independence Screening and Sparsifying Operator)with the training data obtained via deformation potential theory,we propose an efficient and physically interpretable descriptor to evaluate the relaxation time,using tetradymites as prototypical examples.Without any input from first-principles calculations,the descriptor contains only several elemental properties of the constituent atoms,and could be utilized to quickly and reliably predict the carrier relaxation time of a substantial number of tetradymites with arbitrary stoichiometry.

关键词： relaxation arbitrary utilized